The present invention relates to a method and apparatus for determining the topology of a cornea.
Austrian Pat. No. 400 664 discloses an apparatus for analyzing the topology of the cornea, in particular for in vivo or in vitro assessment of the curvature of the anterior surface of the cornea. The analyzing apparatus includes a video keratoscope which uses the conventional placido-process to detect corneal distortion by reflecting alternating black and white rings onto the anterior corneal surface. A support arm is mounted on a motor-operated feed table and carries a contact member or probe. The feed table together with the support arm is so advanced by linear motors in the direction of the cornea that in a first phase (zero position), the probe is moved in position in respect to the cornea without effecting corneal deformation, and in a second phase, the probe is moved toward the cornea to realize an indentation in the .mu.m range. In the first phase, an image is taken of the curvature of the cornea, and after indentation by means of the probe, the operator photographs momentary distortion of the corneal surface. By comparing the images, the determined topographic deviations enable the operator to infer to local, pathological changes of the cornea and to determine possible corneal distortions.